ns16550: move CONFIG_SYS_NS16550 to Kconfig

Move CONFIG_SYS_NS16550 to Kconfig, and run moveconfig.py.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
diff --git a/configs/iocon_defconfig b/configs/iocon_defconfig
index 63f0c37..bc5e026 100644
--- a/configs/iocon_defconfig
+++ b/configs/iocon_defconfig
@@ -5,3 +5,4 @@
 CONFIG_AUTOBOOT_STOP_STR=" "
 # CONFIG_CMD_ELF is not set
 # CONFIG_CMD_NFS is not set
+CONFIG_SYS_NS16550=y